Acquisitions and Dispositions of Businesses (Narrative) (Details)			1 Months Ended								3 Months Ended	12 Months Ended
	Jul. 05, 2022 USD ($) business	Jun. 14, 2021 USD ($)	Nov. 30, 2022 USD ($)	Aug. 31, 2022 business	May 31, 2022 business	Dec. 31, 2021 USD ($) business	Nov. 30, 2021 business	Mar. 31, 2021 USD ($)	Nov. 30, 2019 business	Sep. 30, 2019 business	Mar. 31, 2020 business	Dec. 31, 2022 USD ($) business automotiveDealership restaurant	Dec. 31, 2021 USD ($) business	Dec. 31, 2020 USD ($) business	Jul. 31, 2022	Dec. 28, 2021 USD ($)	Jan. 26, 2021 USD ($)	May 31, 2020 USD ($)
Business Acquisition [Line Items]
Number of businesses acquired | business												7	6	3
Cost of acquisition												$ 143,200,000	$ 392,400,000	$ 96,800,000
Payments to Acquire Businesses, Net of Cash Acquired												130,106,000	351,882,000	20,080,000
Acquisition-related costs						$ 3,000,000						1,700,000	3,000,000	1,100,000
Goodwill expected to be deductible for income tax purposes						80,600,000						38,500,000	80,600,000	3,200,000
Revenues of acquired companies since acquisition date												153,800,000
Operating income of acquired companies since acquisition date												6,300,000
Net gain on sale of businesses												22,679,000	3,789,000	213,302,000
Interest expense												54,403,000	33,943,000	38,310,000
Change in redemption value of redeemable noncontrolling interests												(5,780,000)	549,000	$ 273,000
Finance Lease, Liability, Current												8,697,000
Finance Lease, Right-of-Use Asset												13,835,000
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests												1,200,000	3,508,000
Leaf Group [Member]
Business Acquisition [Line Items]
Cost of acquisition		$ 308,600,000
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Stock Compensation Liabilities Assumed		$ 9,200,000
Automotive [Member]
Business Acquisition [Line Items]
Finance Lease, Liability, Current						4,000,000						5,400,000	4,000,000
Finance Lease, Right-of-Use Asset						$ 4,000,000						$ 5,400,000	4,000,000
CSI Pharmacy Holding Company, LLC [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests			$ 1,200,000
Group of Senior Managers of GHG [Member] | GHC One [Member]
Business Acquisition [Line Items]
Percentage of Distributions Available to Common Unit Holders												20.00%
Graham Holdings Company [Member] | GHC One [Member]
Business Acquisition [Line Items]
Guaranteed Return												8.00%
Percentage of Distributions Available to Common Unit Holders												80.00%
Education [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business							1				2			2
Education [Member] | Kaplan International [Member]
Business Acquisition [Line Items]
Number Of Businesses Disposed | business									1
Education [Member] | Higher Education [Member] | Kaplan University Transaction [Member]
Business Acquisition [Line Items]
Gain Related to Contingent Consideration												$ 4,300,000	$ 3,900,000	$ 3,500,000
Manufacturing [Member] | Hoover Treated Wood Products [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests								$ 3,500,000
Manufacturing [Member] | Joyce/Dayton Corp. [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business										1
Graham Healthcare Group [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business				2	2	2						5	2
Graham Healthcare Group [Member] | Weiss [Member]
Business Acquisition [Line Items]
Percentage of interest acquired						50.10%							50.10%
Redeemable Noncontrolling Interest						$ 6,600,000							$ 6,600,000
Graham Healthcare Group [Member] | Applied Behavior Analysis clinics
Business Acquisition [Line Items]
Percentage of interest acquired															100.00%
Graham Healthcare Group [Member] | Maximum [Member] | Weiss [Member]
Business Acquisition [Line Items]
Percentage of Shares Eligible to be Redeemed						10.00%						10.00%	10.00%
Graham Healthcare Group [Member] | Maximum [Member] | CSI Pharmacy Holding Company, LLC [Member]
Business Acquisition [Line Items]
Percentage of Shares Eligible to be Redeemed												50.00%
Other Businesses [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business														1
Number of Restaurants | restaurant												11
Other Businesses [Member] | Framebridge [Member]
Business Acquisition [Line Items]
Percentage of Shares Eligible to be Redeemed																		20.00%
Redeemable Noncontrolling Interest																		$ 6,000,000
Business Combination, Contingent Consideration, Liability																		$ 50,600,000
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage																		93.40%
Automotive [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business												2	1
Floor plan payable												$ 69,800,000
Number of Stores | automotiveDealership												6
Automotive [Member] | Auto dealerships [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business	2
Floor plan payable	$ 10,900,000
Amount Borrowed to Finance Business Acquisition	$ 77,400,000
Automotive [Member] | Ford auto dealership [Member]
Business Acquisition [Line Items]
Floor plan payable																$ 16,600,000
Amount Borrowed to Finance Business Acquisition																$ 22,500,000
Supplemental Education [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business											1
Kaplan International [Member]
Business Acquisition [Line Items]
Number of businesses acquired | business											1
Securities Subject to Mandatory Redemption [Member] | Graham Healthcare Group [Member]
Business Acquisition [Line Items]
Interest expense												$ 16,500,000	$ 4,100,000	$ 8,500,000
Graham Holdings Company [Member] | Weiss [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent												50.10%
Graham Holdings Company [Member] | CSI Pharmacy Holding Company, LLC [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent						75.00%						76.50%	75.00%
Graham Holdings Company [Member] | Manufacturing [Member] | Hoover Treated Wood Products [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent												100.00%		98.01%
GHC One [Member] | Group of Senior Managers of GHG [Member] | GHC One [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners												5.00%
Pinnacle Bank Term Loan [Member]
Business Acquisition [Line Items]
Loans Payable to Bank						$ 9,558,000						$ 8,433,000	$ 9,558,000
Pinnacle Bank Term Loan [Member] | Graham Healthcare Group [Member]
Business Acquisition [Line Items]
Loans Payable to Bank																	$ 10,600,000
Group of Senior Managers of GHG [Member] | GHC One [Member]
Business Acquisition [Line Items]
Percentage of Contributed Capital												5.00%
Graham Holdings Company [Member] | GHC One [Member]
Business Acquisition [Line Items]
Percentage of Contributed Capital												95.00%